function show_t(type,num,last) {
  var i;
  for ( i=1; i<=last; i++ ) {
    document.getElementById(type+"tabcontent"+i).style.display = "none";
    document.getElementById(type+"tab"+i).className = "";
  }
  document.getElementById(type+"tab"+num).className = "selected";
  document.getElementById(type+"tabcontent"+num).style.display = "block";  
}